audio/msm7630: Fix to enable TTY device

-Connecting TTY device is not showing proper RX and TX values.
-Mismatch in Key values of TTY modes in HAL.
-Change TTY mode string values as per the values in PhoneGlobals.java.

CRs-Fixed: 449513
Change-Id: I53e52b057bb535647731bdd7b99cb065b2e50940